Originally Posted by CREWMAN
Thats the answer i was looking for.
What balls do you sugest and do u fill up all the holes in the spur with balls or just the outer.
Thanks for the help guys.
Please copy and paste this into MS Word so you have saved locally
Building a Diff
I use plain chrome steel diff balls from BMI, IRS, anyone...they are all the same high grade 1/8" ball bearings.
I like to use Schumacher U1301 silicon diff grease or Associated silicon diff grease, the thick type in a plastic cup not the stealth grease in a squeeze tube. Stealth grease is too thin and gets flung out too easy.
The diff balls I buy come in a 100 pack for ~$8. I open the pack over a clean paper tower and dump them out. All diff balls have a coating of oil on them to protect them while they sit on a shelf. I use motor spray carefull to wet them and then roll them on the paper towel to dry them. I then dump them all into the cup of diff grease. I keep them there untill I use them.
When I build a diff I sand both sides of the diff rings with 600 grit wet-dry sandpaper lubricated with a little motor spray untill I see an even finish across the face of the rings. I then clean the rings with motor spray and dry them on a clean paper tower.
Be sure to clean your finger tips with motor spray before touching the diff balls or rings. If you get any bearing oil or traction compound on them from your fingers it will contaminate the diff and mess it up.
I then pluck the diff balls out of the diff grease cup with a small clean flat blade screwdriver and put them in the spur gear. They will carry all the diff grease they need with them. You do not need to put more on the rings. I put a ball in all 12 holes in the outer circle. The inner circle of holes is for the no longer used small diameter "Stealth" diff rings.
Assemble the diff normally but tighten it slowly until you just start to get diff action. If you overtighten it you can dimple the rings and flat spot the balls. Tighten it and check the gear for slipping. As soon as the gear starts to get hard to slip stop.
Mount some tires on the axle. Hold one tire and the gear locked and force the opposide side to turn a few turns. Repeat with the other side. This is called cutting the diff. Cutting the diff smooths out any imperfections in the rings and balls by burnishing them. The diff may have loosened a little from cutting it so readjust it so the gear is very hard to slip (this is tighter than the previous step).
Install a motor and put the car up so the wheel are not touching the table. Run it at meduim throttle and alternatly touch one tire then the other untill it just stops then let go. This will heat up and fling out excess diff grease as well as breaking in the diff. Do this a couple times per side.
Re adjust the diff a final time so it wil not slip and you are done. The diff should be glass smooth. It should spin very freely as if it were really loose but the diff gear should be almost impossible to slip.
If the diff is gritty with new rings and balls replace the outer right side hub bearing.
If the diff is slipping you have some petroleum oil contamination in the diff. Take everything apart and start over after cleaing everything with motor spray.